Alternative-Fuel Vehicles Definitions
Bi-fuel Vehicles - Bi-fuel vehicles have two tanks for two separate fuels. Gasoline is commonly paired with CNG or propane. A switch is used to choose between the two fuels.
Dual-fuel Vehicles - Dual-fuel vehicles have two tanks for two separate fuels. Both fuels are used at the same time in the combustion chamber to produce power. This system is typically used in diesel engines where the diesel fuel is used as a pilot to ignite the other fuel.
Dedicated-fuel Vehicles- Dedicated AFVs use one alternative fuel full-time. Currently available are vehicles designed to run on propane, electricity, compressed or liquefied natural gas, and battery-electric power. Generally, dedicated vehicles provide superior emissions and performance results because their design has been optimized for operations on only one fuel.
FlexFuel - Operates with a common fuel tank designed to run on varying blends of unleaded gasoline with ethanol. The fuel mixture can contain any mixture ratio up to 85% ethanol known as E85.
Hybrid - Operates on two or more energy sources, one of which is electricity. HEVs may combine the engine and fuel system of a conventional vehicle with the batteries and electric motor of an electric vehicle in a single drivetrain. Hybrid vehicles are typically 25-30% more fuel efficient than standard gasoline vehicles and produce fewer emissions due to the greater fuel efficiency. Hybrid vehicles do not count toward EPAct requirements but are considered AFVs under the Governor's EO - 111. The state fleet currently has over 50 light-duty hybrid vehicles.
Diesel - Diesel vehicles are not considered alternative fuel vehicles but do provide higher fuel economy than comparable gasoline versions. Diesel vehicles operate on a compression ignition cycle which is inherently more fuel efficient than a standard gasoline engine. The compression ignition engine is typically 30 - 40% more fuel efficient than a spark fired gasoline engine but produces more emissions on a gallon of fuel basis than gasoline. The majority of the State's heavy-duty fleet utilize diesel engines.
|
